Usually the idea that keeps someone from committing suicide is the fact that they have something to do, something to accomplish, they can't leave something behind. When they have no connections to the world anymore, they are then ready to accept death.
This factor will come for me when I'm of course, an old man. Society has made it a duty for everyone to have a role in life, therefore everyone has a purpose to live. Once mine is done, then I'll welcome death. Even though I'm not religious at all, and I don't believe in heaven or hell, I can stay calm about it.
2012 is a joke though. The theoretical scientists should've considered the fact that 2012 would've arrived at some point >_>. They're no better then those horrible cancer research scientists.
EDIT: I've also considered reincarnation, but thoughts and beliefs are only a byproduct of the brain's function. Natural selection made it big for a reason, so we can live in an enviroment without any natural protection. Therefore, any life after death seems like it wouldn't be a possibility. If all goes well with reincarnation however, I'd like the Universal scientists and Stephen King to be right about the billions of parralel universes and dimensions.
EDIT2: Cancer has been (supposedly) cured. Also, I will give anyone 20 internet cookies if they know what Stephen King book gave the theory I talked about in the above edit.